Power Windows
Power Windows/Sunroof
Purpose of the System
The features of the power windows and sunroof system include:
- One-touch operation in both directions (up/down) on the front windows, down only on the rear windows.
- Anti-trap detection is on the front windows only (initialization required for one touch operation).
- The control of the rear windows is carried out through a Relay Module (RM IV).
- The switches in the center console controls all four windows and the rear window lock out feature.
Principle of Operation
All window operation request signals are digital inputs to the GM.
- Comfort Closing of the windows from the driver's or passenger's lock cylinder when held in the locking position.
- When the ignition key is in accessory or "ON" press the switch to open or close the windows. Window operation is possible with the ignition switched off until a front door is opened or 16 minutes (maximum) has elapsed.
- Power protection against a jammed or seized motor is monitored by tile hall sensors in the window motors. The GM will interrupt the power to a jammed motor. Rear windows utilize current sensing for shut off.
- The one-touch function is activated by momentarily pressing the window switch to the second detent. Window travel will cease when the full up or down position has been reached. One-touch can be canceled by pressing the window switch a second time. Anti-trap is provided by the GM monitoring the door glass movement from the hall sensor. If the door glass encounters resistance in the closing direction ( > 100Nm) the motor will stop and reverse direction for 50 mm of travel.
Window Operation specific to the E36 Convertible:
- Central Window Switch: Located in the center console, the switch will raise or lower all four windows at the same time. The window lowering has the one-touch feature.
- Convertible top operation: Prior to lowering the top, the top control module signals the GM to lower all four windows half way.
- If the top switch is held after the top is fully lowered, the windows will close fully.
- If the top switch is held after the top is fully closed the GM will close the windows.
- With the introduction of the fully automatic convertible top, the comfort close feature of the convertible was also added.
Window Operation specific to the Coupe, Convertible and Z3 Coupe:
The design of the E36 Coupe, Convertible and Z3 Coupe required changes in the window operation.
- When opening the door, the door glass is automatically lowered by approximately 10mm. When the door latch opens (switch closes), the window will drop. It remains down until the door contact switch opens when the door is closed. The window will then raise back into the door seal.
- When the door is closed, the glass is raised back into the seal.
This allows the glass to drop out of the door seal when opening the door and provides a tighter seal when the door and glass are closed.
- The window motor contains a Hall sensor for this feature that is monitored by the GM.
System Components
Window Switches: The signals from the window switches are monitored by the GM.
The power window switches have a second detent position for the purpose of signalling the one touch feature.
Relay Module: The RM IV was added for rear window operation in the 4 door and convertible models only.
Similar to the front window relays in the GM, the Relay Module contains the relays for the rear window motors on these vehicles.
The RM IV is located behind the glove box in the electrical carrier next to the GM.
System Components: Inputs - Processing - Outputs
Initialization of Window Circuits
Initialization of the window circuits is required for the one-touch and anti-trap features to function. Closing the window and holding the switch for an additional two seconds will initialize the system. However the window drive motor switches off automatically after the motor ceases rotation for approximately 0.3 seconds.